1972 Ski-Doo Shop Manual, Page 86Get this manual
1-13-08 (g) Sit the drive chain over shift sprocket teeth(h) Apply hand pressure on outer side of oil seals to push seals against the bearings (fig1-13-23) GEAR BOX (b) Using soft faced hammer, carefully tap shaft into position(c) Install shim, gear change lever, washer and nutTorque nut to 17 ftllbs(d) Using feeler gauge, check that free play of gear change shaft is within tolerance of 0.006 to 0.012 inchIf free play is not within tolerance, record discrepancyRemove nut, washer, gear change lever, shim and gear change shaftDivide ais crepancy by and instaU that amount of shims on gear change shaftInstall shaft into upper housingInstall standard shim and balance of shim(s) on gear change shaftInstall gear change lever on shouldered end of change shaft so that lever and vent pfug hole form 45 degree angleInstall washer and nutTorque nut to 16 ftllb(fig1-13-25)